1. Field of the Invention
The invention relates to an electricity meter for accurately determining the consumption of a given electrical installation.
2. Description of the Prior Art
There are two known types of electricity meters, electromechanical and electronic. Electromechanical meters use a small motor that rotates at a speed which depends on the power consumed. The small motor drives a mechanical counter that stores the values of total power consumed. The mechanical losses due to friction make the system insensitive to low current, below 70 mA. This results in a failure to sense and store power values of below 15.4 W. The calibration of these electromechanical meters is relatively lengthy and the meter cannot be recalibrated after it has suffered a certain amount of wear and tear. Furthermore, the mechanical parts are relatively costly.
Electronic meters are designed to eliminate certain defects of electromechanical meters. Thus, electronic meters have a lower limit of sensitivity. They cost less to manufacture. A meter can be recalibrated following a drift in the performance of its components. Nevertheless, the calibration operations take a great deal of time (for the setting of the potentiometers) and a machine cannot be recalibrated at the place of its use.
There also exist fuzzy logic processors and the concept of fuzzy logic in the prior art, for taking decisions on the basis of input parameters that have low linearity or no linearity and can assume several values for a zone of a curve in a given operation.